Research Article: Unnikrishnan, S., Bais, D., Suryanarayanan, A., Shah, A., & Brockmann, A. (2026). Variation in behavioural maturation in tropical honey bees corresponds with hormonal and molecular differences. Journal of Experimental Biology, 229(8), jeb251399.

Blog Author: Chandan Kumar Pandey and Nikita Yardi

Key highlights: 

• This study explores how two species of Asian honey bees; one that builds open nests on tree branches (Apis florea) and another that lives inside cavities (Apis cerana), differ in how quickly workers mature  and transition to the role of  foragers.
• While both species begin foraging at roughly the same age, the transition is more protracted in A. florea,  spread across a wider window, with greater variation between individuals.
• The hormonal and genetic signals associated with foraging appear ancient and conserved across species. 
• The nurse-associated signals that diverge in both Asian species follow patterns inconsistent with temperate A. mellifera, suggesting the nurse phase may be where tropical and temperate honey bee biology differ.
• Apis florea workers carry unusually high levels of a canonically reproductive protein throughout their lives.

Not all honey bees grow up at the same pace, and that might tell us something profound about how their social life is maintained.

For decades, what we have known about honey bee development has largely come from one species. Apis melifera, the Western honey bee, studied in seasonal temperate climates across Europe and North America. The transition from nurse to forager in A. mellifera is well mapped and replicated many times, becoming the baseline for understanding how honey bee colonies organise themselves. 

Researchers working out of Bengaluru asked what happens when you look at the tropics. They followed two tropical asian honey bee: 1) A. florea, the dwarf honey bee, that builds single-comb nests on tree branches, with workers clustered around it for warmth and protection, and 2)  A. cerana, the eastern honey bee, which tucks its multi-comb nests inside dark tree cavities, tracking hormones, protein, and genes as workers aged. 

The difference in nesting appears to shape how workers develop. A. cerana, transitions to foraging on a tight, almost predictable schedule. A. florea is a more protracted, slower and highly varied transition timeline; some individuals begin foraging within days of emerging, others take weeks. Cavity-nesting bees, protected inside tree hollows or rock crevices, can afford to grow faster and replace foragers more readily. Open-nesting species must maintain a living “curtain” of worker bees surrounding the comb to protect against adverse weather, parasites, and predators.

In both species, a chemical messenger called Juvenile Hormone rises steadily as workers age, mirroring the shift from nurse to forager. This pattern is so consistent across honey bee species that it appears to be an ancient, conserved feature of how these insects develop. 

The divergence from the baseline comes from the nurse side. In the Western honey bee, a protein called vitellogenin is high in nurses and declines with age, part of the molecular machinery that keeps workers nursing before they shift to foraging. In both Asian species, that pattern does not appear. Vitellogenin levels show no meaningful relationship with age or role. In fact, workers of A. florea carry unusually high levels of vitellogenin throughout their lives. Vitellogenin is canonically a reproductive protein, and its persistent presence may indicate that slow-maturing workers may function as living pantries, banking protein reserves the colony can draw on during lean times. BR-C, another nurse-associated signal (gene), showed up more strongly in foragers in both species.

The divergence clusters on one side. The forager-associated signals look the same across tropical and temperate climates. The nurse-associated one does not. This suggests that is where tropical and temperate honey bee biology have gone separate ways. 

Across the two Asian species, and against the temperate baseline, what emerges is that the picture is less settled than it appeared. How a colony is built, where it lives, and the pressures it faces may all have more bearing on how its workers develop than initial studies capture. These two species suggest the baseline has edges that should be explored further.

To access the original article, click here.

Keywords: Asian honey bees, Apis florea, Apis cerana, bee behavior, division of labor, Juvenile Hormone, pollinators, tropical ecosystems.